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1.
Environ Sci Technol ; 57(8): 3166-3175, 2023 02 28.
Artigo em Inglês | MEDLINE | ID: mdl-36780547

RESUMO

Coprecipitation of radionuclides with barite has been studied to remove radionuclides from radioactive liquid waste because of its excellent removal efficiency; however, little information exists concerning the stability of the ions coprecipitated with barite. This study systematically investigated the stability of iodate, selenite, and selenate coprecipitated with barite via leaching tests. These oxyanions were gradually leached from the oxyanion-bearing barite into ultrapure water over time. Leaching of the oxyanions significantly increased in leaching solutions containing NaCl (pH 5.3), NaNO3 (pH 5.9), and Na2SO4 (pH 5.7). Conversely, leaching of the oxyanions was suppressed in KH2PO4 solution (pH 8.5), indicating that phosphate stabilized the oxyanion-bearing barite. The effect of phosphate treatment on oxyanion-bearing barite was further investigated. The results showed that the barite surface was modified with phosphate, and a thin surface layer of a barium phosphate-like structure was formed. The amount of oxyanions leached from the phosphate-treated samples into leaching solutions containing NaCl or NaNO3 was much lower than the amounts leached from the untreated barite samples into ultrapure water. The barite coprecipitation combined with subsequent phosphate treatment may be a promising method to efficiently remove iodate, selenite, and selenate from wastewater and stabilize them as barite coprecipitates.


Assuntos
Sulfato de Bário , Fosfatos , Ácido Selênico , Iodatos , Cloreto de Sódio , Ácido Selenioso , Água/química
2.
Environ Res ; 217: 114874, 2023 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-36457240

RESUMO

Due to the increasing of industrial plastic waste and its refractory characteristics, it is extremely urgent to develop new degradation technology and environmentally friendly catalyst for industrial plastic waste. Manganese oxides are one of the most promising candidates for the catalytic degradation of plastic wastes. However, an improved understanding of the structural properties affecting their catalytic activity is required for high-efficient wastewater treatment. We herein report the surface reactivity effects of δ-MnO2 structural defects with regards to Bisphenol A (BPA) degradation/probe in the presence of peroxymonosulfate (PMS). Four δ-MnOx samples with different Mn(III) contents (different Mn(III)-deficient sample) were prepared and their structural properties as well as surface reactivity were characterized by batch test, ESR and XAFS analysis. For the Mn(III)-deficient sample, BPA removal was principally affected by direct electron transfer, with the adsorbed BPA degraded following hydroxylation. In contrast, a small fraction of Mn(III) substitution in δ-MnO2 could significantly encouraged the activation of PMS to produce SO4-☐and ☐OH, and a BPA degradation via beta scission. Moreover, the Mn(III)-rich δ-MnO2 demonstrate a high BPA removal rate even with a low sample load, which performed well following a reuse of five times. Our results provide a new way for the improvement of δ-MnO2 activity for the use of industrial plastic wastes treatment.


Assuntos
Compostos de Manganês , Óxidos , Óxidos/química , Oxirredução , Compostos de Manganês/química , Elétrons , Peróxidos
3.
Pediatr Surg Int ; 38(12): 1759-1768, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36094546

RESUMO

PURPOSE: The gut microbiota, via the gut-liver axis, plays an important role in the development of intestinal failure-associated liver disease. Here, we investigated whether partially hydrolyzed guar gum (PHGG), a dietary fiber could alleviate liver damage and modulate the gut microbiota in a murine liver injury (LI) model. METHODS: Liver injury was induced in 6-week-old male C57BL/6 mice using an enteral liquid diet composed of parenteral nutrition (LI group) and treated with 5% PHGG (LI/PHGG group). Liver histopathology was examined using oil red O and a tumor necrosis factor-α (TNF-α) labeling. The gut microbiota was examined using 16S rRNA gene sequencing. RESULTS: Lipid accumulation was significantly decreased in the LI /PHGG group when compared with that of the LI group. The area of TNF-α-positive cells was significantly higher in the LI group when compared with that of the control. The principal coordinate analysis (PCoA) revealed pronounced changes in the gut microbiota after PHGG treatment. Linear discriminant analysis of effect size showed that PHGG treatment significantly increased cecal abundance of Parabacteroides. CONCLUSIONS: PHGG alleviated hepatic steatosis following liver injury in mice. The protective effect of PHGG treatment could be associated with increased abundance of Parabacteroides in the cecum.


Assuntos
Microbioma Gastrointestinal , Enteropatias , Masculino , Camundongos , Animais , Fator de Necrose Tumoral alfa , RNA Ribossômico 16S , Camundongos Endogâmicos C57BL , Fígado/patologia
4.
J Environ Sci (China) ; 86: 78-86, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31787192

RESUMO

Permanganate treatment is widely used for disinfection of bacteria in surface-contaminated water. In this paper, the fate of the dissolved permanganate in aqueous solution after contact with cells of Pseudomonas fluorescens was studied. Concomitant accumulation of divalent cations of Mg2+, Zn2+, and Co2+ during precipitation of Mn oxides was also studied. The time course of the Mn concentration in solution showed an abrupt decrease after contact of Mn(VII) with microbial cells, followed by an increase after ~24 hr. XRD analysis of the precipitated Mn oxides, called biomass Mn oxides, showed the formation of low-crystalline birnessite. Visible spectroscopy and X-ray absorption near edge structure (XANES) analyses indicated that dissolved Mn(VII) was reduced to form biomass Mn oxides involving Mn(IV) and Mn(III), followed by reduction to soluble Mn(II). The numbers of electron transferred from microbial cells to permanganate and to biomass Mn oxides for 24 hr after the contact indicated that the numbers of electron transfer from microbial cell was approximately 50 times higher to dissolved permanganate than to the biomass Mn oxides in present experimental conditions. The 24 hr accumulation of divalent cations during formation of biomass Mn oxides was in the order of Co2+ > Zn2+ > Mg2+. XANES analysis of Co showed that oxidation of Co2+ to Co3+ resulted in higher accumulation of Co than Zn and Mg. Thus, treatment of surface water by KMnO4 solution is effective not only for disinfection of microorganisms, but also for the elimination of metal cations from surface water.


Assuntos
Biodegradação Ambiental , Compostos de Manganês/metabolismo , Óxidos/metabolismo , Microbiologia da Água , Poluentes Químicos da Água/metabolismo , Cátions Bivalentes , Cobalto/metabolismo , Magnésio/metabolismo , Poluentes Químicos da Água/análise , Zinco/metabolismo
5.
J Phys Chem A ; 122(41): 8152-8161, 2018 Oct 18.
Artigo em Inglês | MEDLINE | ID: mdl-30248261

RESUMO

We elucidate the application of L3-edge X-ray absorption near edge structure (XANES) spectra to the local structural analysis of lanthanoids in aqueous solution, iron hydroxide, manganese dioxide, and calcium carbonate. The L3-edge XANES spectra of lanthanoid compounds showed sharp white lines. The full width at half-maximum (FWHM) values of lanthanoid aqua ions exhibited a convex tetrad curve in the series variation across the lanthanoid series. The variation is attributable to 4f electron orbitals and can be explained by the refined spin-pairing energy theory. For each lanthanoid, the FWHM values of lanthanoid compounds roughly decreased with increasing local coordination numbers. However, they did not faithfully reflect the local coordination sphere of the lanthanoid complex having a high and distorted coordination sphere and were rather sensitive to their chemical forms. The relationship between the magnitude of the FWHM values was determined by the crystal field splitting or degeneracy of 5d orbitals. The systematic variation of FWHM can be explained by the ligand strength of the ligand molecules (-H2O0, -O-, -OH-, -CO32-, -Cl-, and -O2-) that cause the crystal field splitting. Therefore, the FWHM values of L3-edge XANES of lanthanoid compounds may be more useful in speciation analysis rather than structural analysis.

6.
Odontology ; 103(1): 66-74, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-24276427

RESUMO

Periodontitis is a multifactorial disease associated with genetic and environmental factors. Single-nucleotide polymorphisms (SNPs) are associated with susceptibility to common diseases such as diabetes and periodontitis. Although the oral cavity is exposed to various organisms, the conditions are well controlled by innate and acquired immune systems. Antimicrobial peptides (AMPs) play an important role in the innate immune system; however, the association of AMP-SNPs with periodontitis has not been fully elucidated. This study investigated the relationship between AMP-SNPs and periodontitis in Japanese. One hundred and five Japanese subjects were recruited, which included patients with aggressive, severe, moderate and mild periodontitis, and age-matched healthy controls. Genomic DNA was isolated from peripheral blood and genotypes of SNPs of ß-defensin-1 and lactoferrin genes (DEFB1: rs1799946, rs1800972 and rs11362; and LTF: rs1126478) were investigated using the PCR-Invader assay. Protein level of AMPs in gingival crevicular fluid (GCF) was quantified by ELISA. Case-control studies revealed that the -44 CC genotype of DEFB1 (rs1800972) was associated with periodontitis (OR 2.51), particularly with severe chronic periodontitis (OR 4.15) and with combined severe and moderate chronic periodontitis (OR 4.04). No statistical differences were found in other genotypes. The ß-defensin-1 concentrations in GCF were significantly lower in subjects with the -44 CC genotype of DEFB1 than in those without this genotype. No significant differences between GCF concentrations of AMPs and other genotypes were detected. The -44 CC genotype of the ß-defensin-1 gene (DEFB1 rs1800972) may be associated with susceptibility to chronic periodontitis in Japanese.


Assuntos
Predisposição Genética para Doença , Periodontite/genética , Polimorfismo de Nucleotídeo Único , beta-Defensinas/genética , Adulto , Estudos de Casos e Controles , Ensaio de Imunoadsorção Enzimática , Feminino , Genótipo , Humanos , Japão , Masculino , Reação em Cadeia da Polimerase
7.
J Colloid Interface Sci ; 669: 1006-1014, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-38759591

RESUMO

Reducing iron by hydroxylamine (HA) can promote the generation of reactive oxygen species (ROS) in the Fenton reaction and play a crucial role in the degradation of organic pollutants. However, the performance of this system at wider environmental thresholds is still not sufficiently understood, especially in the highly alkaline environments resulting from human activities. Here, we assessed the impact of solution pH on organic pollutant degradation by goethite with the addition of HA and H2O2. The solid phase variation and ROS generation were analyzed using Mössbauer spectroscopy, X-ray absorption near edge structure spectroscopy, and electron paramagnetic resonance analysis. This study found that under alkaline conditions, the system can continuously scavenge organic pollutants through oxygen-mediated generation of free radicals. At lower pH levels, organic pollutant decomposition, exemplified by the breakdown of bisphenol A (BPA), is primarily driven by the Fenton reaction facilitated by iron. As pH increases, hydroxyl radical (•OH) production decreases, accompanied by decreased BPA removal efficiency. However, the removal efficiency of BPA increased significantly at pH > 9. At pH 12, the removal of BPA exceeded that of the acidic condition after one hour, which is consistent with observations in soil system studies. Unlike the Fenton reaction, which is not sensitive to oxygen content, the removal of BPA under alkaline conditions occurs only under aerobic conditions. H2O2 is hardly involved in the reaction, and the depletion of HA becomes a critical factor in the decomposition of BPA. Importantly, in contrast to acidic conditions, where the dramatic decomposition of BPA occurs mainly in the first 10 min, the decomposition of BPA under alkaline conditions continued to occur over the 2 h of observation until complete removal. For natural systems, the remediation of pollutants depends more on the active time of ROS than on their reactivity. Therefore, this idea can reference pollution remediation strategies in anthropogenically disturbed environments.

8.
J Colloid Interface Sci ; 661: 317-332, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38301469

RESUMO

Adsorption reactions of various cations on clay minerals have different effects on their environmental behaviors depending on the molecular-scale adsorption structure. Some cations form outer-sphere complexes via hydration, while others create inner-sphere complexes through dehydration. This preference dictates their environmental impact. However, the factors controlling these complex formations remain unclear. Furthermore, research on the adsorption preferences of radium (Ra) is lacking. Thus, this study conducted the first EXAFS study of Ra2+ adsorbed on clay minerals and showed that Ra2+ forms inner-sphere complexes on vermiculite, which can be surprising because Ra2+ is a divalent cation and prefers to be hydrated. In order to investigate the factors controlling the complex formations, this study conducted systematic EXAFS measurements and DFT calculations for alkali and alkaline earth metal cations. The results showed the importance of the size-matching effect between the adsorbed cation and the cavity of the tetrahedral sheets and that the complex formation can be estimated by the combination of the ionic radius and hydration enthalpy of the adsorbed cation. Furthermore, this study also analyzed environmental core samples. Their results showed the fixation of Ra2+ by clay minerals and the controlling factors can effectively predict cation environmental behavior.

9.
Chemosphere ; 355: 141837, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38554863

RESUMO

Radioactivity of Ra isotopes in natural waters is of serious concern. Control of 226Ra concentrations in tailings ponds, which store waste from U ore extraction processes, is an important issue in mill tailings management. In this study, we tested microbially formed Mn(IV) oxide as an adsorbent for removal of Ra in water treatment. Biogenic Mn(IV) oxide (BMO) was prepared using a Mn(II)-oxidizing fungus, Coprinopsis urticicola strain Mn-2. First, adsorption experiments of Sr and Ba, as surrogates for Ra, onto BMO were conducted in aqueous NaCl solution at pH 7. Distribution coefficients for Ba and Sr were estimated to be ∼106.5 and ∼104.3 mL/g, respectively. EXAFS analysis indicated that both Sr and Ba adsorbed in inner-sphere complexes on BMO, suggesting that Ra would adsorb in a similar way. From these findings, we expected that BMO would work effectively in removal of Ra from water. Then, BMO was applied to remove Ra from mine water collected from a U mill tailings pond. Just 7.6 mg of BMO removed >98% of the 226Ra from 3 L of mine water, corresponding to a distribution coefficient of 107.4 mL/g for Ra at pH ∼7. The obtained value was convincingly high for practical application of BMO in water treatment. At the same time, the high distribution coefficient indicates that Mn(IV) oxide can be an important carrier and host phase of Ra in the environment.


Assuntos
Óxidos , Rádio (Elemento) , Rádio (Elemento)/análise , Adsorção
10.
JBJS Case Connect ; 12(2)2022 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-35696716

RESUMO

CASE: A 77-year-old woman with bilateral symptomatic atypical femoral fractures (AFFs) and severe anterolateral bowing due to long-term bisphosphonate administration was treated using stainless elastic intramedullary nails. Weight-bearing pain disappeared immediately after surgery. Radiographs obtained 1 year postoperatively showed fracture healing. CONCLUSION: Although intramedullary nail insertion has been recommended for symptomatic incomplete AFFs, in cases of severe bowing, rigid nail insertion was often challenging, and the complication rates were higher than those with mild bowing. The advantage of our method is easy insertion, suggesting effective treatment.


Assuntos
Fraturas do Fêmur , Fixação Intramedular de Fraturas , Idoso , Pinos Ortopédicos , Feminino , Fraturas do Fêmur/diagnóstico por imagem , Fraturas do Fêmur/cirurgia , Fêmur , Consolidação da Fratura , Humanos
11.
Sci Total Environ ; 821: 153265, 2022 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-35065112

RESUMO

Upon release into the aquatic environment, the surface of microplastics (MPs) can be readily colonized by biofilms, which may enhance the adsorption of contaminants. In this study, industrial-grade polystyrene (PS) of about 4 mm in size (MP4000-1), food-grade PS of about 4 mm in size (MP4000-2), and Powder PS of about 75 µm in size (MP75) were co-cultured with a model freshwater fungus, namely Acremonium strictum strain KR21-2, for seven days to form biofilms on their surface. We also determined the changes in surface physicochemical properties of the biofilm-covered MPs (BMPs) and the heavy metal adsorption capacity of the original MPs and BMPs. The results revealed that the biofilms improve the adsorption of heavy metals on MPs, and the particle size of MPs plays a crucial role in biofilm colonization and adsorption of heavy metals by BMPs. MP75 can carry more biofilm on its surface than that of the two MP4000s and form heteroaggregates with biofilms. In addition, there were more functional groups on the surface of BMP75 than on the surface of the two BMP4000s, which could promote the electrostatic interaction and chemical association of heavy metals. Moreover, BMP75 exhibited a higher capacity to adsorb Cu and reduce Cr (VI), which may be related to the functional groups in its biofilm. Overall, this study showed that after biofilms colonization, BMPs of smaller size have more significant potential as a metal vector, and the particle size deserves more scientific attention during the risk assessment.


Assuntos
Metais Pesados , Microplásticos , Biofilmes , Microplásticos/toxicidade , Tamanho da Partícula , Plásticos/química
12.
J Cachexia Sarcopenia Muscle ; 13(2): 945-954, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-35170256

RESUMO

BACKGROUND: The sarcopenia index (SI), calculated as the ratio of serum creatinine to cystatin C levels, reflects skeletal muscle mass and strength. Patients with hip fracture (HF) and sarcopenia have poor functional outcomes, and many require long-term care after surgery. We hypothesized that the SI can predict preoperative and early postoperative functional outcomes. METHODS: Preoperative serum creatinine and cystatin C were measured to calculate the SI for patients with surgically treated HF (n = 130, mean age: 87.8 ± 6.9 years). Walking ability before and 2 weeks after surgery was assessed, and patients were dichotomized into independent and assistance groups. To assess the validity of the SI, we examined its correlation with the quality [computed tomography (CT) value] and quantity (cross-sectional area) of the muscles around the hip on the non-operated side, which were preoperatively measured using CT. Receiver operating characteristic (ROC) analysis was performed to evaluate the prognostic value of the SI. RESULTS: The SI of the preoperative independent (n = 77) and assistance groups (n = 53) significantly differed (70.2 ± 12.4 and 60.1 ± 9.8, respectively, P < 0.000001). At 2 weeks after surgery, the SI was significantly higher in the independent group (n = 31, 73.0 ± 14.9) than in the assistance group (n = 99, 64.0 ± 10.7, P = 0.0003). In the preoperative independent group, 28 could walk independently after surgery (SI: 74.8 ± 14.0) while 49 required assistance (SI: 67.7 ± 10.6, P = 0.01). For patients with femoral neck fracture (FNF), the SIs were significantly higher in the postoperative independent group (78.6 ± 15.7) than in the postoperative assistance group (63.2 ± 10.9, P = 0.002). Logistic regression analysis showed that the odds ratio (95% confidence interval) of the SI for postoperative walking ability was 0.95 (0.91-0.99, P = 0.03). The correlations of SIs with CT values and cross-sectional areas were as follows: iliopsoas at the apex of the femoral head, r = 0.40, P < 0.001 and r = 0.49, P < 0.001, respectively; rectus femoris at the level of the lessor trochanter, r = 0.26, P = 0.007 and r = 0.37, P < 0.001, respectively. ROC analysis for predicting postoperative walking ability in preoperative independent patients with HF and FNF revealed areas under the curve (95% confidence interval) of 0.63 (0.50-0.76) and 0.80 (0.65-0.96), respectively. CONCLUSIONS: In patients with HF, the SI correlated with preoperative walking ability and could predict postoperative walking ability. Among patients who could walk independently before surgery, those with high SIs could walk independently early in the postoperative period. The SI is beneficial for estimating walking ability in patients with HF.


Assuntos
Cistatina C , Sarcopenia , Idoso , Idoso de 80 Anos ou mais , Creatinina , Humanos , Período Pós-Operatório , Sarcopenia/diagnóstico , Caminhada
13.
Injury ; 53(11): 3781-3785, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-36045029

RESUMO

INTRODUCTION: The incidence of the fragility fractures of the pelvis (FFPs) has been increasing in recent years. Operative treatment is effective in patients who are unable to ambulate due to pain. Anterior subcutaneous internal fixation (ASIF) is a minimally invasive and stable fixation used to treat the FFPs, with few reported vascular complications. However, we experienced a case in which the rod directly pressed the common femoral artery (CFA). OBJECTIVES: The purpose of this study was to examine the relationship between the rod position as defined by ASIF and the CFA in the FFPs patients, and between BMI and the rod-to-CFA distance. MATERIALS AND METHODS: Pelvic measurements were performed in 47 patients with FFPs using trauma CT. We identified the anterior inferior iliac spine (AIIS) on both sides in axial CT images. Next, we performed a simulation study using the CT images, in which the virtual fixation rod was bent according to the shape of the patients' abdomen in the supine position. The shortest rod-to-CFA distance when the virtual rod was positioned directly above the AIIS in the CT image was measured. The correlation between body mass index (BMI) and the rod-to-CFA distance was measured. RESULTS: The average shortest rod-to-CFA distance was 18.4 ± 11.1 mm, and the simulated rod compressed the CFA in three of the 47 cases (6.4%). A statistically significant positive correlation between BMI and the rod-to-CFA distance was found (r = 0.47, p = 0.001). CONCLUSIONS: The course of the CFA should be confirmed before ASIF surgery, and if there is danger of compression of the CFA such as in patients with low BMI, the rod-to-AIIS distance should be adjusted to the optimal distance. However, considering the disadvantages, such as decreased stability of the fixation, when adjusting the rod-to-AIIS distance, and skin irritation and abrasion by the rod, ASIF is not recommended in cases in which the rod is close to the CFA.


Assuntos
Fraturas Ósseas , Ossos Pélvicos , Lesões do Sistema Vascular , Humanos , Ossos Pélvicos/diagnóstico por imagem , Ossos Pélvicos/cirurgia , Ossos Pélvicos/lesões , Artéria Femoral/diagnóstico por imagem , Artéria Femoral/cirurgia , Fixação Interna de Fraturas/métodos , Fraturas Ósseas/cirurgia , Pelve , Abdome , Lesões do Sistema Vascular/diagnóstico por imagem , Lesões do Sistema Vascular/cirurgia
14.
Sci Rep ; 12(1): 13164, 2022 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-35915210

RESUMO

The human being dynamically and highly controls the head-trunk with redundant mechanical structures to maintain a stable upright standing position that is inherently unstable. The posture control strategies are also affected by the differences in the conditions of sensory inputs. However, it is unclear how the head-trunk segmental properties are altered to respond to situations that require appropriate changes in standing posture control strategies. We used a data-driven approach to conduct a multipoint measurement of head-trunk sway control in a quiet standing position with differences in the conditions of sensory inputs. Healthy young subjects with 22 accelerometers attached to their backs were evaluated for head-trunk vibration during quiet standing under two conditions: one with open eyes and one with closed eyes. The synchronization of the acceleration and the instantaneous phase was then calculated. The results showed that the synchronization of acceleration and instantaneous phase varied depending on the visual condition, and there were some continuous coherent patterns in each condition. Findings were that the structural redundancy of the head-trunk, which is multi-segmental and has a high mass ratio in the whole body, must be adjusted adaptively according to the conditions to stabilize upright standing in human-specific bipeds.


Assuntos
Postura , Posição Ortostática , Aceleração , Humanos , Equilíbrio Postural , Vibração
15.
iScience ; 25(8): 104763, 2022 Aug 19.
Artigo em Inglês | MEDLINE | ID: mdl-35992079

RESUMO

Radium is refocused from the viewpoint of an environmental pollutant and cancer therapy using alpha particles, where it mainly exists as a hydrated ion. We investigated the radium hydration structure and the dynamics of water molecules by extended X-ray absorption fine structure (EXAFS) spectroscopy and ab initio molecular dynamics (AIMD) simulation. The EXAFS experiment showed that the coordination number and average distance between radium ion and the oxygen atoms in the first hydration shell are 9.2 ± 1.9 and 2.87 ± 0.06 Å, respectively. They are consistent with those obtained from the AIMD simulations, 8.4 and 2.88 Å. The AIMD simulations also revealed that the water molecules in the first hydration shell of radium are less structured and more mobile than those of barium, which is an analogous element of radium. Our results indicate that radium can be more labile than barium in terms of interactions with water.

16.
Chemosphere ; 266: 129104, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33310356

RESUMO

Radioactive iodine (129I) is of great concern owing to its high mobility in the environment and long-term radiotoxicity. However, there is a lack of effective techniques for removing iodate (IO3-) from aqueous solution. This study aims to develop a new technique for removing radioactive iodate from contaminated solution by using barite (BaSO4). We examined the coprecipitation mechanism of iodate by barite at the molecular level to determine the optimum conditions for iodate removal. Results showed that iodate was effectively removed from the aqueous solution by coprecipitation even in the presence of competitive anions. Based on comparison of our method with previous techniques, the iodate removal efficiency by barite was determined to be about two orders of magnitude greater than that by hydrotalcite-like layered double hydroxide at 10 mmol L-1 Cl-. Extended X-ray absorption fine structure analysis indicated that the incorporated iodate was strongly bound to the crystal lattice of barite by substituting the sulfate site in the structure when the iodine concentration was low. The charge compensation problem from the IO3- substitution in the SO42- site was achieved by the substitution of Na+-IO3- pairs at the nearest Ba2+ site. Given the high removal efficiency and strong binding of iodate to barite, coprecipitation with barite is a promising tool for removing radioactive iodate from various aqueous solutions contaminated with iodate.


Assuntos
Iodatos , Neoplasias da Glândula Tireoide , Sulfato de Bário , Humanos , Radioisótopos do Iodo , Sulfatos
17.
Sci Total Environ ; 755(Pt 2): 142598, 2021 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-33065509

RESUMO

Since the Chernobyl and Fukushima nuclear power plant accidents, extensive research has focused on the distribution and cycle of radiocesium in forest systems. Nevertheless, direct chemical speciation analyses of Cs by spectroscopic methods are limited by the low abundances of stable Cs as well as radiocesium in trees. In this study, we investigated coordination structures of Cs in 133Cs-doped bark, sapwood, heartwood, needle, and branch samples of trees collected in Fukushima by extended X-ray absorption fine structure (EXAFS) spectroscopy. We examined four representative tree species in Fukushima, Cryptomeria japonica, Pinus densiflora, Quercus serrata, and Eleutherococcus sciadophylloides. EXAFS spectra suggested that Cs was adsorbed as an outer-sphere complex on all parts of the four species, with electrostatic binding to negatively charged functional groups in components of tree tissues. These results were supported by extraction experiments where more than 98.5% of the sorbed Cs was desorbed from all parts of each tree species using 1 M CH3COONH4. Sorption experiments of Cs on cellulose, an important component of plant cell walls, were carried out in ultrapure water, NaCl, and KCl solutions. The Kd values for cellulose and solutions were not high enough to fix Cs, considering the composition of sap in trees. Overall, the results of this study are consistent with previous field observations indicating that radiocesium is translocated in mobile form to metabolically active tree parts.


Assuntos
Acidente Nuclear de Fukushima , Monitoramento de Radiação , Poluentes Radioativos do Solo , Césio , Radioisótopos de Césio/análise , Japão , Poluentes Radioativos do Solo/análise , Árvores
18.
Medicine (Baltimore) ; 98(19): e15531, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-31083201

RESUMO

RATIONALE: Cerebral venous thrombosis (CVT) is a cerebrovascular disorder that causes venous infarction and intracerebral hemorrhage (ICH) with occlusion of cerebral veins, and its incidence is estimated to be 5 per 1 million people per year, accounting for 0.5% to 1.0% of all strokes. Despite advances in the recognition of CVT, the diagnosis and treatment may be difficult because of the diversity of underlying risk factors. A rare case of ICH due to CVT during surgery is described. PATIENT CONCERNS: A 69-year-old-man presented to our department with a history of paralyzed extremities after a backward fall and head trauma. The patient had a history of pharyngeal cancer treated with neck dissection and radiotherapy. Computed tomography (CT) images showed continuous ossification of the posterior longitudinal ligament (OPLL) at C2-5 levels and a fracture line at the caudal end plate of the C5 body. The diagnosis was traumatic cervical cord injury, so that posterior cervical decompression and fusion was performed. Immediately after surgery, the patient developed an epileptic seizure and the disturbance of consciousness persisted. MR venography and contrast CT images showed absence of flow from the superior sagittal sinus to the transverse sinus. DIAGNOSES: The diagnosis in this case was ICH due to CVT. INTERVENTIONS: The patient was treated with anticoagulation using unfractionated heparin. OUTCOMES: The patient ultimately made a complete recovery from CVT. LESSONS: Although risk factors for CVT are diverse, head and neck injury, patient's position during surgery, and postoperative radical neck dissection for pharyngeal cancer might have been the factors in this case. While the measures to prevent this disease are uncertain, early diagnosis and treatment are needed to avoid serious complications.


Assuntos
Hemorragia Cerebral/etiologia , Vértebras Cervicais/cirurgia , Trombose Intracraniana/complicações , Complicações Intraoperatórias/etiologia , Traumatismos da Medula Espinal/cirurgia , Idoso , Descompressão Cirúrgica , Humanos , Masculino , Esvaziamento Cervical , Neoplasias Faríngeas/radioterapia , Neoplasias Faríngeas/cirurgia , Fusão Vertebral
20.
Microbes Environ ; 33(4): 402-406, 2018 Dec 28.
Artigo em Inglês | MEDLINE | ID: mdl-30404972

RESUMO

We herein described a new microbial isolation method using the interaction between the floating aquatic plant, duckweed, and microbes. We harvested microbial cells from Japanese loosestrife roots and co-cultivated these cells with aseptic duckweed using artificial inorganic medium for the plant for four weeks. During the co-cultivation, some duckweeds were collected every week, and the roots were used for microbial isolation using a low-nutrient plate medium. As a result, diverse microbial isolates, the compositions of which differed from those of the original source (Japanese loosestrife root), were obtained when the roots of duckweed were collected after 2 weeks of cultivation. We also successfully isolated a wide variety of novel microbes, including two strains within the rarely cultivated phylum, Armatimonadetes. The present study shows that a duckweed-microbe co-cultivation approach together with a conventional technique (direct isolation from a microbial source) effectively obtains more diverse microbes from a sole environmental sample.


Assuntos
Araceae/microbiologia , Bactérias/isolamento & purificação , Técnicas Bacteriológicas/métodos , Técnicas de Cocultura/métodos , Consórcios Microbianos , Bactérias/classificação , Bactérias/genética , Bactérias/crescimento & desenvolvimento , DNA Bacteriano/genética , Lythrum/microbiologia , Filogenia , Raízes de Plantas/microbiologia , RNA Ribossômico 16S/genética
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